When agricultural produce such as grapes and strawberries is picked, it is packed in the field in relatively flat, open-topped trays or boxes. These boxes are stacked on pallets for shipping and storage, a stack often being sixteen, eighteen or more boxes high.
The boxes are consumed in large numbers, running into many millions each growing season, and the cost of packaging must be kept at a minimum. Nevertheless, the boxes must be strong enough to protect the produce against degradation. They should be lightweight and have a large capacity in comparison to their external dimensions.
Generally, the boxes are made from folded paperboard blanks. Prior to folding, the blanks are flat sheets that require comparatively little room and are easily shipped. Once folded, however, they become bulky, are relatively susceptible to damage, and are difficult to ship. For this reason, it is often desired to fold the blanks in the field at the site where produce is to be packed.
Folding of the blanks in the field is generally a labor intensive and, therefore, expensive operation. Moreover, some boxes are folded improperly in the field resulting in a loss of produce. These difficulties have led some growers to use machine folded boxes that are shipped to the packing site in an assembled condition, despite the above-mentioned disadvantages of the approach.
A primary objective of the present invention is to provide a method and device for folding blanks that will permit boxes to be easily, quickly and reliably assembled at the site. A further objective is to provide such a method and device that can be used to assemble improved boxes having increased strength and stacking ability.